Someone once said, “Just when you think things can’t get any worse, they don’t.” We’re supposed to think that life is self-correcting, that it’s darkest before the dawn.

That’s a comforting thought. Problem is, it encourages a false optimism, especially about our universities. Go back 50 years, and liberals outnumbered conservatives in the academy by 3 to 1. Now it’s 12 to 1. In some departments, like history, it’s 30 to 1.

So if you think things are self-righting, you might expect that we’d snap back to a 3-to-1 ratio. But that’s not going to happen.

First, we’ve seen the rise of frankly ideological sub-disciplines — for race, gender and sexual orientation — where conservatives are wholly excluded as a matter of course.

Second, there’s no sign people in other departments are bothered by the ideological imbalance. The ratio of liberals to conservatives may be 12 to 1, but for newer academics it’s 20 to 1. The conservatives who remain in higher ed are generally over 65, and they’re aging out.

In other words, it’s going to get worse.

That’s why we need to be on the lookout for signs that colleges will try to squeeze out the remaining academic deplorables who harbor disturbing conservative tendencies. The schools can’t fire a conservative simply for being a conservative, so the University of Arkansas has proposed a workaround: Fire a teacher for his lack of collegiality — for his unwillingness to work productively with others — which would come down to pretty much the same thing at a hard-left college.

The proposal is an attack on academic tenure, and if implemented in American universities we’ll see even fewer conservatives on faculty. If you think colleges wouldn’t apply their newfound power to fire people with right-wing beliefs, ask yourself why so few of them were hired to begin with.

We might be tempted to shrug this off if we saw much evidence of learning going on in America’s colleges and universities. We don’t.

In “Academically Adrift,” Richard Arum and Josipa Roksa found that 36 percent of students showed no improvement in analytic abilities and writing skills after four years in college.

Bear in mind that we’re talking about students tested between the ages of 17 and 21, and that we’d expect some improvement in problem-solving skills for everyone over that period, whether they’re in college or not, just because they’re older.

So forget all the puffery about how we have the best colleges in the world. We have many of the richest ones, but the reality is that the average American school isn’t as good as the average school in many other countries. Even at the best of our schools, there isn’t much learning going on.

What’s happened is that ideological brainwashing has taken the place of learning in American higher ed. A college that sees its mission as turning out little liberals isn’t going to welcome intellectual curiosity or spirited debate. Just the opposite. The kind of person who questions dubious assumptions is likely to be mocked, investigated by the diversity police and charged with a hate crime.

Nor is there any reason to think American higher ed can cure itself. Fifty years back, some university administrators were still able to curb faculty craziness. But that’s long gone. Boards of trustees are incorrigibly spineless, and college presidents have worked out their own corrupt bargain with their professors: You can teach anything you want or nothing at all, but don’t object if I pay myself a million-dollar salary.

So what’s the answer? Some conservatives like the idea of abolishing tenure, but that’s not going to help when it’s the liberals who’ll do the firing. What’s left, the only thing that’s left, is the power of the purse, the taxpayer subsidy to higher ed.

And that’s why you’ll find small cuts to higher ed in the draft tax bills circulating around Congress. Republicans have smartened up and begun to see American higher ed the way reformers saw the monasteries 500 years ago: rich, corrupt, lazy — and ripe for a break-up.

F.H. Buckley teaches at Scalia Law School and is author of the forthcoming “The Republic of Virtue: How We Tried to Ban Corruption, Failed, and What We Can Do About It.”